Quote:
Originally Posted by sidewayz2
I took our GXP to the track last night. I wanted to see if it could get the 14 sec qtr like GM says. Well here it is.... It was a mild sticky night in Donaldsonville, LA. very high humidity about 68-70 degrees. The car has exactly 505 miles on it when I arrived there. I let the turbo cool down for about an hour and then I lined up. I left very soft because the car is so new. I just punched it from a dead ,no boost no rev. The car was so smooth and well behaved no wheel spin or any problems. She ran a 14.60 at 93 miles per hour. I only did 1 run cause it's my wife ALPHA 1's car and she said she would seriously divorce me if I muffed it up. Next time I am going to spool it up with a little power breaking and see if it can achieve the GM numbers. The only thing that I found wierd is that the turbo under boost squeals like a banshee. I know it is probably the blow off valve but man is it loud. It happens about 14psi and doesn't quit until you lift the pedal. Is it supposed to be that loud. It sounds like a constant bleed not a shoosh sound. At the track everyone was like we could see the car and about half track all you could hear was the wheeeeee..... sound. I said it was because the car was having fun but then I explained it was a turbo 4 cyl and it was the blow off valve. I guess what I am asking is if the VERY loud blow off valve is normal or do I have an issue.WILL SOME OF YOU OTHER GXP OWNERS RESPOND??  |
If your turbo makes a "fweeeee!" noise under boost, you have an airleak somewhere in the system. (sounds similar to blowing on a blade of grass between your thumbs). Get it back to the dealer and have them check all of the intake system attachments including the attachments to the intercooler. Tell them NOT TO OVERTORQUE the attachments, but make sure they are all correctly assembled.
The noise you describe is not normal, and could explain some of the subpar performance.
The other question is: did you do this with traction control on or off?
